Initial commit

src/users/users.service.ts

@@ -0,0 +1,39 @@
+import { Injectable } from '@nestjs/common';
+import * as fs from 'fs';
+import * as path from 'path';
+
+export interface User {
+  id: number;
+  fullName: string;
+  createdAt: string;
+}
+
+@Injectable()
+export class UsersService {
+  private readonly filePath = path.resolve(__dirname, '..', 'data', 'users.json');
+
+  private readUsers(): User[] {
+    if (!fs.existsSync(this.filePath)) {
+      return [];
+    }
+    const data = fs.readFileSync(this.filePath, 'utf8');
+    return JSON.parse(data);
+  }
+
+  private writeUsers(users: User[]): void {
+    fs.writeFileSync(this.filePath, JSON.stringify(users, null, 2), 'utf8');
+  }
+
+  findAll(): User[] {
+    return this.readUsers();
+  }
+
+  create(user: User): void {
+    const users = this.readUsers();
+    const existingUser = users.find((u) => u.id === user.id);
+    if (!existingUser) {
+      users.push(user);
+      this.writeUsers(users);
+    }
+  }
+}